Monday, November 2, 2015

Hold the mushrooms please

“A Moldy Planet: Fungal Infections Are Everywhere,” a Monday morning Annual Meeting session, sounded a bit like the title of an old-school pulp comic. In fact, it made me want to frantically wash my hands. But when I left the session, I felt infinitely better. Public health was on the job.

The session offered some interesting insights into fungal diseases, which we don’t hear about that often. I mean, fungi are so cute and adorable. How dangerous could they be, right? Well, it turns out the image in my head of a red-capped mushroom with white polka dots isn’t as innocent as it appears.

“Fungal diseases don’t get a lot of love,” said session presenter Greg Greene, an epidemiologist at the Centers for Disease Control and Prevention.

Greene focuses on Cryptococcus diseases, opportunistic infections that kill half a million people every year in sub-Saharan Africa. The fungus is found in soil just about everywhere in the world — all of us have probably been exposed, Greene said — but our immune systems are strong enough to protect us. But for those with compromised immune systems, Cryptococcus can get in the bloodstream, spread to the spinal column and brain and lead to meningitis. Fortunately, there’s an easy, cheap and commercially available test for the infection, and early detection significantly improves long-term survival. But patients have to be treated promptly and have to adhere to antifungal treatment — “there lies the challenge to this intervention,” Greene told session attendees.

To confront that challenge, public health workers are working to implement three main strategies: provider-initiated screening, automatic testing in a laboratory for those at high risk, and point-of-care screening followed by the immediate initiation of treatment. Today, 19 countries have adopted screening interventions for Cryptococcus. For example, Greene said, Rwanda adopted a strategy of provider-initiated screening in 2014 and today, providers and laboratory technicians throughout the country have been trained in the screening strategy. In South Africa, automatic lab testing has resulted in more than 55,000 samples screened and a growth in testing capacity from two labs in one province to 10 labs in four provinces. And in Lesotho, point-of-care screening has been conducted by layworkers since 2014.

But there is a key to such success, Greene said: “Government has to be behind this.”

In Washington state, public health workers take a one-health approach to coccidioidomycosis, also known as valley fever. People contract valley fever by breathing in microscopic fungal spores, although most people won’t get sick from it. Some people who do get sick will need anti-fungal medication. Session presenter Ron Wohrle, a public health veterinarian at the Washington State Department of Health, said the first endemically reported cases of valley fever in Washington state occurred in 2010-2011; fast forward to 2014, and 21 cases were reported, of which three were locally acquired. Though Wohrle said officials believe infections are under-reported.

To get a better handle on the fungal infection, Wohrle and his public health colleagues launched some surveillance efforts, taking and testing targeted soil samples from suspected exposure sites. To date, nearly 200 samples have been collected from 11 sites in two counties, with 13 samples testing positive. In terms of the one-health approach, Wohrle said he’s also working with 14 veterinarian hospitals to collect canine serum samples — so far, about 260 samples have been tested, with 2.7 percent testing positive for coccidioidomycosis. In the future, Wohrle said he and his colleagues hope to develop habitat suitability models that could help predict where valley fever risks are likely to be high.

But like lots of health threats, fungal infections are becoming resistant to medications as well, said session presenter Angela Cleveland of the Mycotic Diseases Branch at CDC. Cleveland reported that candidemia, a bloodstream infection caused by the yeast candida, is the most common fungal infection and one that’s associated with high rates of morbidity and mortality. In fact, candidemia is now the top cause of bloodstream infections in health care settings, Cleveland told session attendees.

Cleveland said CDC is particularly concerned that some strains of candida are becoming resistant to first-line and second-line antifungal treatments. And because there’s no mandatory reporting on candidemia, the true burden is unknown. However, in 2008, CDC began a surveillance effort in Maryland, Georgia, Tennessee and Oregon. Overall, it seems like resistance trends are on an upward climb, though resistance appeared to concentrate in certain hospitals.

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